U.S. Pat. No. 2,976,266 broadly discloses copolyesters prepared from 4,4'-biphenyldicarboxylic acid and certain aliphatic glycols. Copolyesters of 4,4'-biphenyldicarboxylic acid (BDA), 1,6-hexanediol (HD), and ethylene glycol (EG) are broadly disclosed in column 2, line 70 of U.S. Pat. No. 2,976,266 in a general listing along with other aliphatic glycols useful in this disclosed invention. The copolyester of BDA, HD, and EG is not specifically disclosed. U.S. Pat. Nos. 3,842,040 and 3,842,041 disclose the homopolyester of 4,4'-biphenyldicarboxylic acid and ethylene glycol.
U.S. Pat. No. 4,742,151 discloses ultra-high-molecular weight polyesters prepared from aromatic dicarboxylic acids and alkylene glycols containing from 2 to 6 carbons having an intrinsic viscosity greater than 1.5. 4,4'-Biphenyldicarboxylic acid is disclosed in a list of dicarboxylic acids useful to the disclosed invention.
German Offenlegungsschrift, DE No. 1935252, discloses polyesters of two aromatic dicarboxylic acids which include 10 to 50 mol % 4,4'-biphenyldicarboxylic acid, 50 to 90 mol % of terephethalic acid and the two glycols ethylene glycol and 1,4-cyclohexanedimethanol. Japanese patent, Kokai Tokkyo Koho JP No. 57/198726 discloses copolyesters containing 25-80 mol % 4,4'-biphenyldicarboxylic acid with various aliphatic glycols and aromatic dicarboxylic acids.
Homopolyesters of 4,4'-biphenyldicarboxylic acid and certain aliphatic glycols are disclosed in journal literature. Homopolyesters of 4,4-biphenyldicarboxylic acid and ethylene glycol, 1,4-butanediol, and 1,6-hexanediol are disclosed by Meurisse et al., in the British Polymer Journal, Volume 13, page 57 (1981) (Table 1). Jackson and Morris include a review of homopolyesters from 4,4'-biphenyldicarboxylic acid and various aliphatic glycols in the Journal of Applied Polymer Science, Applied Polymer Symposia, 41, 307-326 (1985). Krigbaum et al., disclose relatively low molecular weight homopolyesters from 4,4'-biphenyldicarboxylic acid and various aliphatic glycols in the Journal of Applied Polymer Science, Polymer Letters Edition, 20, 109-115 (1982). Low molecular weight homopolyesters of 4,4'-biphenyldicarboxylio acid are aIso disclosed by Wanatabe et al., Macromolecules, 21(1), p. 278-280 (1988), and Krigbaum et al., Polymer, 24(10), p. 1299-1307. Jpn. Kokai Tokkyo Koho JP No. 6,236,821 [86,236,821] (1986) also discloses low molecular weight polyesters from 4,4'-biphenyldicarboxylic acid and 1,4-butanediol prepared below their melting temperatures in a nonvolatile liquid. Polyesters of 1,6-hexanediol and 4,4'-biphenyldicarboxylic acid are disclosed in Kobunshi Ronbunshu, Vol. 44(12), 983-986 (December 1987) having limiting viscosity number of about 0.31.
Heretofore, copolyesters from 4,4'-biphenyldicarboxylic acid, ethylene glycol and 1,6-hexanediol have been unknown.